package com.yehun.validator;

import javax.validation.ConstraintValidator;
import javax.validation.ConstraintValidatorContext;
import java.util.Arrays;

public class IdcardConstraintValidator implements ConstraintValidator<Idcard, String> {


    public void initialize(Idcard idcard) { }

    public boolean isValid(String idcardField, ConstraintValidatorContext cxt) {
        if(idcardField == null) {
            return false;
        }
        char[] id = {};
        for (int i = 0; i < idcardField.length(); i++) {
            id = Arrays.copyOf(id, id.length + 1);
            id[id.length - 1] = idcardField.charAt(i);
        }
        boolean ret = this.verifyFormat(idcardField);
        if (ret) {
            ret = this.verify(id);
        }
        return ret;
    }

    /**
     * 身份证格式的正则校验
     */
    private boolean verifyFormat(String idcard) {
        return idcard.matches("^\\d{15}$|^\\d{17}[0-9Xx]$");
    }

    /**
     * 身份证最后一位的校验算法
     */
    private boolean verify(char[] id) {
        int sum = 0;
        int w[] = { 7, 9, 10, 5, 8, 4, 2, 1, 6, 3, 7, 9, 10, 5, 8, 4, 2 };
        char[] ch = { '1', '0', 'X', '9', '8', '7', '6', '5', '4', '3', '2' };
        for (int i = 0; i < id.length - 1; i++) {
            sum += (id[i] - '0') * w[i];
        }
        int c = sum % 11;
        char code = ch[c];
        char last = id[id.length-1];
        last = last == 'x' ? 'X' : last;
        return last == code;
    }

}